The following relates generally to wireless communication, and more specifically to beam and symbol selection to transmit a random access channel (RACH).
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems, (e.g., a Long Term Evolution (LTE) system). A wireless multiple-access communications system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).
Some wireless communication systems may operate in millimeter wave (mmW) frequency ranges (e.g., 28 GHz, 40 GHz, 60 GHz, etc.). Wireless communication at these frequencies may be associated with increased signal attenuation (e.g., path loss), which may be influenced by various factors, such as temperature, barometric pressure, diffraction, etc. As a result, signal processing techniques such as beamforming (i.e., directional transmission) may be used to coherently combine signal energy and overcome the path loss in specific beam directions. In some cases, a device may select a beam direction (e.g., beam identification (ID)) for communicating with a network by selecting the strongest beam from among a number of reference signals transmitted by a base station. However, the strongest beam may be associated with an access time period that results in a significant delay before an access message may be sent. This may result in a delay in accessing the network, or an increased interruption in reestablishing a connection.